Understandable. Self-doubt, not uncommon in a situation like this. I won't lie to you, if he truly wants to leave, he will, depending on how strongly he agrees with that 10% of himself. If he loves you more than he wants to leave, then he'll stay. It really is ultimately up to him to decide. It likely won't be instant, you'll be able to catch things here and there if he's really starting to get serious about leaving. Until that actually happens, I don't think you have anything to worry about.